1. Field of the Invention
This invention relates generally to the field of data communication protocols and, more particularly, to a system for sharing a bi-directional data bus between a master device and a slave device.
2. Description of the Related Art
A master chip and a slave chip may share a data bus. The master chip may write data to the slave chip and/or read data from the slave chip through the data bus. In some situations, the slave chip may be configured to receive a transfer request from the master chip and service the transfer request in a deterministic amount of time. Thus, when the master chip asserts a read request to the slave chip and has a pending write to perform next, the master chip may wait a deterministic amount of time, assume control of the data bus, and perform the write associated with the write request. After the deterministic amount of time, the slave unit will have supplied the requested data on the data bus, the requested data will have been captured by an input port of the master chip, and thus, it will be safe to assume control of the data bus.
In other situations, the slave chip may not be able to service a transfer request in a deterministic amount of time. In such situations, the master's scheme of assuming bus control after a fixed amount of time may be inappropriate. Thus, there exists a need for a system and method of arbitrating bus control between a master unit and a slave unit especially in situations where the slave's servicing time for reqeusted transactions is non-deterministic.